Open-end metal bending brake



i g- 1949- R. L. WEBB 2,478,854

OPEN END METAL BENDING BRAKE Filed April 22, 1948 the beam, the ends are sufiiciently' rigid to hold their position and, consequently, they will not rise up or float rearwardly.

The invention also contemplates means for selectively positioning the clampingbeam with regard to the gauge of the metal to be bent,'a's well as certain strengthening members for the bed-' plate and bending beam, all of .,which will be de scribed later with reference tothe drawings.

The preferred embodiment of the invention is j 2 a rear elevation showing a sheetof metal inserted in one end of the brake and clamped preparatory to bending; Fig. 3 a'section alongline III-III of Fig. 1; and Fig.4 a section similar to that ofFig. 3, but showing the position of the various parts during bending.

Referring to the drawings, the brake includes a bedplate I towhich a clamping beam 2-is secured by means of a pair ofcam mechanisms 3 and 4. This beam is considerably shorter than the plate and is provided. with a front beveled edge 6 against which metal inserted between the beam and plate is bent, the bendingbeing done by a bending beam 1 which is pivotally attached to the bedplate by hinges 8, the beam also bein provided with a pair of handles 9 by which it can be swung upwardly to bend the metal. In order to provide the brake with suflicient strength and rigidity for bending metal of normal gauges, the bedplate and clamping beam are reinforced by angles H and i2 '(Fig 3) and by rods l3 and I4 (Fig. 1), the rods both having adjustable members l6 and IT to vary their tension. The brake as a whole is supported on aisupport which, preferably, is detachablyconnected to the bedplate so that the support and. the brake can be separated and each part easilycarried.

When the brake is not in use, its clamping beam is automatically raised'clear of the bedplate by a pair of coil springs. l8and IS, the ends of which are received in holesprovided in the plate and the beam. Previously mentioned cam mechanisms 2 and 3 provide the force for clamping the metal to be bent, each of these including a securing member or bolt 2| anchored, inthe bedplate and extending vertically upwardly from it through an opening 22providednearthe center.

of the clamping beamr Preferably, a lug 23 is welded or otherwise secured to the under side of the bedplate to provide additional rigidity for the cam bolt. The portion of the bolt extending above the clamping beam isenlargedto receive a pivot pin 26 each end of whichsuppor'ts a'cam 21, the cam being provided with an operating handle 28. Between the camahd the upper surface of the clamping beam'arepositioned a pair of slid-l ably contacted discs 3|and'32; the lower surface of the upper disc beingconvex and the loweridisc having a matching eoncaveupper surface. The cam, of course, exerts its pressure through the discs to the clamping beam; the discs bin'g pro-. vided to evenly distribute the cam pressure to the beam, as well as, to'take up" forces which-.othep.

4 wise would tend to bend the cam bolt, all as will be described later in greater detail.

From the description so far, it can be recognized that the brake provided is an open-end type since the spaces between bolts 2| and the extreme ends of the clamping beam are unobstructed. As mentioned before, the principal difliculty with such open-end brakes is that these extreme ends have a tendency to spring and float during the bending operation. This invention avoids such by providing apair of fulcrum members or blocks 33, these blocks, preferably, being bolted to the rear side of the clamping beam and have a lower rearwardly beveled portion 34 projecting downwardly from the bottom surface of the beam towardthe bedplate.

Further, the blocks each are positioned a spaced distance inwardly from beam-securing bolts 2|, this distance depending upon the characteristics of the metal from which the clamping beam is fabricated.

The. general purpose of each block 33 is to provide a fulcrum. about 'which the clamping beam can be bowed or arched upon application of cam pressure, and for the purpose of reducing the pressure necessary to so arch the beam, it is preferred to initially provide the beam with a slight downward bow. The function of the blocks and the results of bowing theclamping beam can be understood best from a description of a bending operation, which is begun by inserting the metal and swinging the cam handles downwardly to exert pressure against the clamping beam. Although both of the cam mechanisms can be operated simultaneously, it usually will be preferred to use one of them at a time since this type of brake is adapted to make a certain bend at one end of the brake after whichthe metalis transferred to the other end whereanother bend is made. In describing the operation, the results of the applied cam pressure will be considered in a step-by-step progression until the metal is finally clamped, although of course, the actual application of pressure is by a smooth and continuous downward swing of the cam handles. Upon the application of the initial pressure, beveled projection 34 of the fulcrum block is brought into contact with the upper surface of the plate. Further pressure then causes the clamping beam to tilt or rock forwardly on its rounded tip into the position shown in Fig. 4, in'which the extreme ends of the clamping beam contact the inserted metal while the central portion of the beam is clear of the metal by a slight fraction of an inch.

To permit the beam to rock forward in this man ner, openings 2i through which beam securing bolts 2| extend, as well as the beam openings through cam discs, are made larger than the bolts and also are inclined at an angle (Fig. 3), from the verticaLaxis of the bolt, this rocking action being shown in Figs. 3 and 4. With the beam so engaged, additional clamping force ex erts a pressure which bows the rear portion of the beam over the fulcrum block and also forces the central portion of the beveled edge of the beam downward into tight clamping contact with theinsertedjmetal',The bowing of the beam operates to throw a considerable portion of the downward force of ,the cam pressure into the end portions of i the .beam, thi'sforce, at least, being sufficient 'to maintaintlie rigidity of the beam during the bending operation'and resist tendencies to spring. 1. Thejexact forces which are set up in the clamping beam when it is bowed and bent aroundthe rearward portion of the fulcrum blocigscan only be surmised, but from observagamete tion ofa brake: in operation reappears that; :in f

addition to the downward force, certain "for wardly acting torsional rorces iare set up which hold the ends of. the beam: forwardly and resist floating; i

' As previously stated, the cam mechanisms each includes a :pair of slidably contacting disc's 3| andi32 which are 'espeoially usefuliin an openend brake which i's'bowed in the manner taught herein. Their use will be appreciated better if it be considered that, shouldthe cams act directly against the clamping beam instead of through these discs,.the rocking movement "of they beam into clamping engagement with the metal would exert a great pressure against the bolts which eventually would bend them. With the discs positioned as theyarathis force 'is'taken up by the sliding of one disc over theother in the.

manner indicated in 4. Also, this sliding causes cam pressure to be transmitted-vertically to the beam and distributes the :pressure evenly over the beam.

The invention alsocontemp'lates means'to initially position theolamping beam inthe most de sirable position for 'bending=any.-.particular gauge of sheet metal. Such members consist of two pairs of set screws, eaehpair having a-front and a rear screw -38 and 39 threaded. into'transverse openings provided in the clamping beam. -Ascan be noted in Figs. 3 or 4, the screws project inwardly toward the 'clalpingbeam securing bolts so that, when tightened, they will move the clamping beam laterally with respect to the bolt. Assuming then that i't-is desiredtobend2'0gauge sheet metal, the clampingbeam first is set upon the b-edplate, the rearscrews' tihtightened against the bolts a-suificie'n-t amount to move the front beveled edge of the beam into'exact' alignment with the front of the bedplatezan'd :front screws 38 then brought :j'ust into conta'ct with the bolts.

The next operation is to unscrew "the front bolts an amount equal to the thickness or gauge metal, this operation leavingaspace bet'ween the: front edge of the bolt anditsbeamandd isc open ings which corresponds to thethickness of the metal. Asa consequence,.durihgthe bending of the metal, the ciampingzbeam can ie't'fa'it a distarice equal to the metal thickness-thisrtreat ing being from thepositioh of the-beam in- F-ig'. 3 to that of Fi 4. As a'resularthebends madeare accurate and sharp and there is'no stretchin'g or tearing of the metal;

. A nuinber of the advantages bf th'e'biake described above will be readll yiappieeiated; It is both light and inexpensive to nianufaoture. By

the use (if the particuiar mechanism, "the bends can be made quickiyahdduring the-bendins-the cam pressure will toedistributed evenlyso as to improve the'rigidity-orthe beani. Also, the cam discs protect the 'icla'inpin'g' bolts against being bent by the great ierce whichniust'beex erted to bow the beam overthe fulcrum mem bers. Further, an open-end brake is provided which permits a nurnbero'f'bends not possible on a zclosed end type, onesucn tommonlyrequired bend being the bending of one portion of a leng'th i '1 :iect while the remaining portion :7 is "left" un bent. For example, it m'ay b'e desire'd'lto bend up both end portions oi a-s'heetand leave the con portion lying in a "plane of the sheet *as a tongue member. To do -sothe sheet nrst' "is slittwice to divide the poitions to be bent fromthe centraiton' ue and then the rig'iit handportion b nt i-n- 'the' left-liand open end of the machine; and the left ha'ndi ortion in the righehand end;

brake is quickly and easily convertible intoa closed-end brake of-the type haV-i'n-g the im rove ments ofthe brake shown and desoribedin my copending application, Serial No. 763,815;v filed July 26, 1947. This conversion is desirable when lengths of metal must be bent which are longerthan the space between the bolts-and-the clamp ing beam ends are required. Aside from thefulcrum blocks of the' present invention, the princepaldiilerenoe in'theclose-end brake of this for mer application is thatits beam is securedatits ends to the bedplate. The-securing means, pref erabI-y, are threaded bolts similar to 1001155 -21 and are part of cam "mechanisms substantially "the same as that described above. -Also the =closed-' end beam carries downward projections to "rock its beveled edge into clamping engagement with the metal. 7 v

The present open-end brake is adapted tor ready conversion simply by forming "a pair :or openings 4! and 42 in each end of its "bedplate. Gp'enings 4! are sized to receive the'beam' secur ing bolts and openings to receive coil springs, or the like, to raise the beam fromthe bedplate. Conversion is made simply by removing the open' end clamping beam by unscrewing its bolts 21,- and then substituting the closed-end beam by screwing its bolts into openingsM at the beam ends. s

- According to the provisions of the patent statutes, I have explained the principle and mode of operation of my inventionand have illustrated and described what I now consider to represent its best embodiment. However, I desire to haveit understood that, within the s'copdof theappend ed claims, the invention may bepract'iced otherwise than as specifically illustrated'and-described.

" I claim: p a

1. An open-'ended sheet metal bending braise comprising a bedplate, a clamping beam having a beveled working edge, clamping beam lifting means for raising said beam clear of "saidplate to permit insertion of metal therebetween, cam mechanism for pressing said beam downwardly against said plate and clamping" said insertedmetal, said-mechanisrn includingabeam securing member anchored in said-bedplateandprojectin'g vertically upwardly throughanenlarged opening provided in the central portion ofs'aicl clam ing beam whereby a substantial length of said'beahi projects outwardly ofsaid securing member, and

a fulcrum member disposed betweensaid beam tra l portion 'ofsaid-clamping'beainiwh'ereby it and bed late and spaced inwardlyef said beam securing member; downward pressure O'HV'SZRTCI beam initially moving its beveled edge into con tact with said inserted metal and then forcefully pressing the metal clamping length of the beam into metal clamping engagement-said force caus ing' said beam to bow about saidfulcrum member whereby sufiicient strength is imparted to the bowed end to firmly clamp 'tl'iemetal'dliring' ti bending operation. V

2. 'An open ended sheetmetal bending brase comprising a be'dplate, a clampingbeam having a beveled working edge, clamping "beam liftingmeans for raising said beam cle'ar'of said plate'f to permit insertion of metal therbetwee'n, cammechanism for pressing said clamping bean'f downwardly against said pl ate and clamping said inserted metal, said mechanism includinga beam; seeu member anchored in sa'id bedpl ate and projecting vertically'upwardly' through the eensubstantiallength of said' beam projects out- Wardly, of said securing member, said member mounting a pair of slidably contacted discs and being reciprocab-le with respect to said beam and discs, said discs operating to evenly distribute the cam pressure to the clamping beam to absorb bending forces actin on said member, and a fulcrum member disposed between said beam and bedplate and spaced inwardly of said beam securing member, downward pressure on said beaminitially moving its beveled edge into contact with said inserted metal and then forcefully pressing themetal clamping length of the beam into metal clamping engagement, said pressure causing said beam to bow about said fulcrum member whereby sufilcient strength is imparted to the bowed beam to firmly clamp the metal during a bending operation.

'3. An open-ended sheet metal bending brake comprising a bedplate, a rockable clamping beam carried by said plate and having a beveled front edge, clampin beam lifting means for raising said beam clear of said plate to permit insertion of metal therebetween, a pair of cam mechanisms for pressing said beam downwardly against said plate and clamping said inserted metal, each of said pair including a beam securing member anchored in said bedplate and projecting upwardly through an opening provided in said clamping beam a relatively, short distance from its center, said member mounting a pair of slidably contacted discs and being reciprocable with respect to said beam and discs, said discs operating during therocking of the beam and the bending of the metal to absorb forces tending to bend the securing member and to evenly distribute the cam pressure to the clamping beam, and a fulcrum member disposed between said beam and bed-plate and spaced inwardly of said beam securin members, said fulcrum member contacting said plate when said beam is cam pressed downwardly and causing said beveled edge of the beam both to rock forwardly into contact with said inserted metal, further cam pressure then forcing the metal clamping length of said beveled edge into metal clamping engagement, said further pressure causing said beam to bow about said fulcrum member whereby sufiicient strength is imparted to the bowed beam to firmly clamp the metal during a bending operation.

4. An open-ended sheet metal bending brake comprising a bedplate, a rockable clamping beam carried by said plate and having a beveled front edge, clampin beam lifting means for raising said beam clear of said plate to permit insertion of metal therebetween, a pair of cam mechanisms for pressing said beam downwardly against said plate and clamping said inserted metal, each of said pair including a beam securing member anchored in said bedplate and projecting upwardly through an opening provided in said clam-ping beam a relatively short distance from its center, said member mounting a pair of slidably contacted discs and being reciprocable with respect to said beam and discs, said discs operating during the rocking of the beam to absorb forces tending to bend the securing member and to evenly distribute the cam pressure to the clamping beam, and a fulcrum block for each of said pair of cam mechanisms, each of said blocks projecting downwardly from said clampin beam and being disposed a set distance inwardly from each of said beam securing members, said downward projections contacting said plate when said beam is cam-pressed downwardly and causin said beveled edge of the beam to rock forwardly into contact with said inserted metal, further cam pressure then forcing the metal clamping length of said beveled edge into metal clamping engagement, said further pressure causing said beam to bow'about a fulcrum member whereby sufficient strength is imparted to the bowed beam to firmly clamp the metal during a bending operation.

5. An open-ended sheet metal bending brake comprising a bedplate, an arched clampin beam having a beveled working edge, clamping beam lifting means for raising said beam clear of said plate to permit insertion of metal therebetween, cam mechanism for pressing said beam downwardly against said plate and clamping said insertedmetal, said mechanism including a beam securing member anchored in said bedplate and projecting vertically upwardly through an enlarged opening provided in the central portion of said clamping beam whereby a substantial length of said head: projects outwardly of said securing member, and a fulcrum member disposed between said beam and bedplate and spaced inwardly of said beam securin member, downward pressure on said beam initially moving its beveled edge into contact with said inserted metal and then forcefully pressing the metal clamping length of the beam into metal clamping engagement, said force causing said beam to bow about said fulcrum member whereby sufficient strength is imparted to the bowed end to firmly clamp the metal during a bending operation.

6. An open-ended sheet metal bending brake comprising a bedplate, a rockable arched clamping beam carried by said plate and having a beveled front edge, clamping beam lifting means for raising said beam clear of said plate to permit insertion of metal therebetween, a pair of cam mechanisms for pressing said beam downwardly against saidplate and clamping said inserted metal, each of said pair including a beam securing member anchored in said bedplate and projecting upwardlythrongh an opening provided in said clamping beam a relatively short distance from its center, said member mounting a pair of discs slidably contacting and being reciprocable with respect tosaid beam and discs, said discs operating during the rocking of the beam and the bending of the metal to absorb forces tending to bend the securing member and to evenly distribute thecam pressure to the clamping beam, a fulcrum member disposed between said beam and bedplate and spaced inwardly of said beam securing members, said fulcrum member contacting said plate when: said beam is cam pressed downwardly and causing said beveled edge of the beam to rock forwardly into contact with said inserted metal, further cam pressure then forcing the metal clamping length of said beveled edge into metal clamping engagement, said further pressure causing said beam to bow about said fulcrum member whereby sufilcient strength is imparted to the bowed beam to firmly clamp the metal during a bending operation.

7.-An open-ended sheet metal bending brake comprising a bedplate, a rockable clamping beam carried by said plate and having a beveled front edge, clamping beam lifting means for raising said beam clear of said plate to permit insertion of metal therebetween, a pair of cam mechanisms for pressing said beam downwardly against said plate'and clamping said inserted metal, each of said pair including a beam securlng member anchored in said bedplate and projecting upwardly through an opening provided in said clamping beam a relatively short distance from its center, said member mounting a pair of slidably contacting discs for distributing cam pressure and absorbing forces tending to bend said securing member, said discs and clamping beam being provided with securing member receiving openings of greater diameter than said member for permitting said beam to be eselectively positioned on said plate with regard to the gauge metal being bent, means for moving said beam into said selected position, and a fulcrum member disposed. between said beam and bedplate and spaced inwardly of said beam securing members, said fulcrum member contacting said plate when said beam is cam pressed downwardly and causing said beveled edge of the beam to rock forwardly into contact with said inserted metal, further cam pressure then forcing the metal clamping length of said beveled edge int-o metal clamping engagement, said further pressure causing said beam to bow about said fulcrum member whereby sumcient strength is imparted to the bowed beam to firmly clamp said metal during a bending operation.

8. An open-ended sheet metal bending brake comprising a bedplate, a rockable clamping beam carried by said plate and having a beveled front edge, clamping beam lifting means for raising said beam clear of said plate to permit insertion of metal therebetween, a pair of cam mechanisms for pressing said beam downwardly against said plate and clamping said inserted metal, each of said pair including a beam securing member anchored in said bedplate and projecting upwardly through an opening provided in said clamping beam a relatively short distance from its center, said member mounting a pair of slidably contacting discs for distributing cam pressure and absorbing forces tending to bend said securing member, said discs and clamping beam being provided with securing member receiving openings of greater diameter than said member for permitting said beam to be selectively positioned on said plate with regard to the gauge metal being bent, a pair of beam-positioning set screws for each of said cam mechanisms, said screws of each pair extending transversely through said clamping beam into contact with opposite sides of said securing member and operating to move the beam into said selected position, and a fulcrum member disposed between said beam and bedplate and spaced inwardly of said beam securing members, said fulcrum member contacting said plate when said beam is cam pressed downwardly and causing said beveled edge of the beam to rock forwardly into con- 10 tact with said inserted metal, further cam pressure then forcing the metal clamping length of said beveled edge into metal clamping engagement, said further pressure causing said beam to bow about said fulcrum member whereby sufficient strength is imparted to the bowed beam to firmly clamp said metal during a bending operation.

9. An open-ended sheet metal bending brake comprising a bedplate, a clamping beam having a beveled working edge, clamping beam lifting means for raising said beam clear of said plate to permit insertion of metal therebetween, cam mechanism for pressing said beam downwardly against said plate and clamping said inserted metal, said mechanism including a threaded bolt anchored in said bedplate and projecting vertically upwardly through an enlarged opening provided in the central portion of said clamping beam whereby a substantial length of said beam projects outwardly beyond said securing member, and a fulcrum member disposed between said beam and bedplate and spaced inwardly of said threaded bolt, downward pressure on said beam initially moving its beveled edge into contact with said inserted metal and then forcefully pressing the metal clamping length of the beam into metal clamping engagement, said force causing said beam to bow about said fulcrum member whereby sufficient strength is imparted to the bowed end to firmly clamp the metal during a bending operation, said beam being provided at each end with a threaded opening for receiving beam securing bolts of an alternatively usable closed-end brake beam.

ROBERT L. WEBB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

